Frankfurt Quasar Monitoring

PHL 1811
Object data

  Cross-Identifications  QSO J2155-0922, FBQS J2155-0922, QSO B2152-0936
  FIRST J215501.4-092224, CXO J215501.5-092224
  IRAS F21523-0936, 2XMM J215501.4-092223
  Equat. coordinates   RA  21 55 01.4     DE  -09 22 24     (J2000)    
  Constellation   Capricornus
  Type   QSO
  Redshift   z=0.194 (4)   /   z=0.190 (2)
  Distance (2) (3)   745 Mpc
  Total mag range (mv) (5)   14.0 - 15.4
  Catalog Magnitude (1)   13.90
  Absolute Magnitude (1)   -26.5 MB
  Light Travel-Time (2)   2.228 × 109 yrs
(1) Véron-Cetty & Véron 2006, A&A 455, 776
(2) NASA/IPAC Extragalactic Database
(3) Co-Moving Radial Distance
(4) CDS Strasbourg
(5) Literature

Finding chart

The finding chart contains the following brighter galaxies:
LEDA 190747, 16.3 mB, 0.5´× 0.4´
LEDA 190768, 16.9 mB, 0.3´× 0.3´
LEDA 190773, 16.5 mB, 0.5´× 0.3´

Comparison stars

star B V
1 14.325 (0.000)
13.692 (0.023)
2 14.551 (0.025)
13.898 (0.024)
3 15.308 (0.085)
14.683 (0.014)
4 15.809 (0.000) 15.055 (0.015)
5 15.690 (0.016) 15.131 (0.014)
comparison stars from APASS (DR6)

Colour chart
Credit: DSS2  /  Size 14´× 14´ /  Chart by S. Karge

Light curve

PHL 1811 is a bright quasar in north-eastern Capricornus, close to the constellation Aquarius. PHL 1811 was discovered in 1962 as a blue stellar object by the Palomar-Haro-Luyten Survey (PHL), searching for blue stellar objects. The "real" discovery goes back to 1997 during the FIRST Bright Quasar Survey (FBQS), a follow up investigation of data received during the FIRST-Radio Survey, carried out by the Very Large Array (VLA). During a check-up of the radio position of PHL 1811 with the POSS 1 photographic plates, a blue stellar object of R=13.87 / B=14.13 was found as the optical counterpart (see colour chart above). At the time of discovery, PHL 1811 was the second brightest quasar ever detected at z > 0.1 (after 3C:273). Follow-up spectroscopic investigations in 1997 with the Multi Mirror Telescope (MMT) revealed a Narrow-Line Seyfert 1-spectrum (NLS1) with a redshift of z=0.192, which led to the quasar classification. A redshift of z=0.192 means a distance of a little more than 2×109 light-years. So quasar PHL 1811 can be best described as a radio quiet, high-luminosity Narrow-Line Seyfert 1. PHL 1811 was first published as a quasar in the 10th edition of the Catalogue of Quasars and Active Nuclei (Véron-Cetty & Véron, 2001).

Quasar PHL 1811 is a small amplitude variable object with a total range of about 1.5 mag in the optical. The Frankfurt Quasar Monitoring programme has detected the quasar as a bright stellar object ranging between 14.0 mag and 14.4 mag. Visual observers need at least an 8- to 10-inch telescope or larger to glimpse this stellar object. Even for observers with large aperture telescopes this quasar remains a stellar object. CCD observers, as well as visual observers, shall use the comparison stars given above.

PHL 1811 is located in the north-eastern part of Capricornus, very close to the constellation Aquarius. Some 2° west of quasar PHL 1811, the two stars 46 Cap and 47 Cap guide the observer to the quasar position. The larger area (10°-15°) around quasar PHL 1811 offers some interesting deep sky objects for the dedicated observer. First there are three globular clusters from the Messier catalog: M2, M30 and M72. Secondly, two prominent planetary nebulae shall not be missed: NGC 7293, the Helix-Nebula, and NGC 7009, the Saturn-Nebula.

Stargazers who like to observe another interesting quasar may focus on MRK 509, a very bright 13-mag quasar at a distance of about 400 million light-years, 17° W of PHL 1811. MRK 509 is one of the nearest quasi-stellar objects known.

Becker, R.H., White, R.L., et al. 2001, ApJS, 135, 227; The FIRST Bright Quasar Survey. III. The South Galactic Cap.
Gaskell, C.S., et al. 2006, ASP Conf. Ser., 390, 1; Optical Variability of the Three Brightest Nearby Quasars.
Gregg, M.D., Becker, R.H., White, R.L., et al. 1996, AJ, 112, 407; The First Bright QSO Survey.
Leighly, K.M., Halpern, J.P., et al. 2001, AJ, 121, 2889; FIRST Observations of the Second-Brightest Quasar.
Karge, S.; Helle Quasare für 8- bis 10-Zoll Teleskope. Ein Beobachtungsführer zur visuellen Beobachtung von
     Quasaren und BL Lacertae Objekten; Frankfurt 2005.
Véron-Cetty, M.-P., Véron, P. 2001, A&A 374, 92; A Catalogue of Quasars and Active Nuclei: 10th edition.
Véron-Cetty, M.-P., Véron, P. 2003, A&A 412, 399; A Catalogue of Quasars and Active Nuclei: 11th edition.
Véron-Cetty, M.-P., Véron, P. 2006, A&A 455, 776; A Catalogue of Quasars and Active Nuclei: 12th edition.
Véron-Cetty, M.-P., Véron, P. 2010, A&A 518, 10; A Catalogue of Quasars and Active Nuclei: 13th edition.


© Stefan Karge  /  last obs. 2022-11-20